The correspondence, including letters, signed Christmas cards and Royal Wedding invitations, were all sent from Diana to nursery teacher Margaret Hodge, who worked alongside the former Lady Diana Spencer at a small kindergarten in London, when the future royal was known as just "Miss Diana."

"It's heavenly up here, just having the opportunity to do what you like and walk for miles," the princess wrote of her September 1981 honeymoon with Prince Charles at Balmoral.

"I've vanished down many a hole," she wrote, of falling down rabbit holes during their walks together. "The husband having not realised – typical."

Written in girlish handwriting and sometimes hard to decipher, the letters and Christmas cards reveal a very personal side of a very public figure, and document the building, and break-up, of a family.

"I ought to finish now and give a hug to my other half," she signs off playfully in one note to Hodge.

"When she started out she was obviously deeply in love with Prince Charles," James Grinter, an auctioneer who has viewed the collection, told "Good Morning America."

"It seems like from the early letters she doesn't really know what she's letting herself in for."

Glimpse of a Royal Life

When William was born, Diana described to Hodge the maternal experience of, "Looking strangely besotted at this small package making strange gaga noises."

A later letter includes link-smudged fingerprints left by William on a letter in which Diana thanks Hodge for a fifth wedding anniversary card.

"You are really wonderful to have sent us such a lovely card on our wedding anniversary -- the five years have flown by and what with two little men to look after its [sic] not surprising," the note, written on Kensington Palace letterhead, reads.

Later letters share the pain of her very public divorce from Prince Charles in 1992, an experience the two woman could share.

"Unfortunately they both went through quite messy divorces," Grinter said. "So from that point of view they kept in touch, they had something in common that bound them together."

Despite the tumultuousness of her marriage and life, all played out under the glare of the royal spotlight, the letters show little sign of her unhappiness and often have an upbeat tone.

"I know she was very much in love with Prince Charles and she just wanted to be loved in return," Hodge told British newspaper the Daily Mail.

Hodge, 69, says she is selling the letters, valued at more than $30,000, reluctantly because she wants to have a level of [financial] comfort in her old age.

The significance of the letters, a royal collection so personal rarely comes on the market, and the great reservoir of love for Princess Diana that exists still nearly 14 years after her death, could make Hodge a very comfortable woman.

"They're very hard things to value in all honesty because a lot of it is down to sentiment," said Grinter. "You only need two people to get carried away and they could fetch, well, we'll see."